Tuning structure for radio sets



y 4, 1943. s. s. cRAMEE v 2,318,572

I TUNING STBUCTURE FOR RADIO SETS Filed Dec. 6, 1941 2 Sheets-Sheet 1 i INVENTOR 1 1 grave? ATTORNEY M y 1943- s. s. CRAMER 2,318,572

TUNING $TRUCTURE FOR RADIO SETS Fiied Dec. 6, 1941 2 sheets-sheet 2 INVENTOR fia l/l-(jurmer BY a, ATTORNE Patented May 4, 1943 UNITED STATES PATENT OFFICE TUNING STRUCTURE FOR RADIO SETS Stanley S. Cramer, Haddon Heights, N. J.

Application December 6, 1941, Serial No. 421,861

21 Claims. (01. 74-10 This invention relates to tuning structures especially adapted for use with radio receiving sets, and especially to tuning structures of the pushbutton type wherein any one of a number of push buttons is moved inwardly to tune in a desired station for which the parts of that particular slidable member are adjusted.

Different types of mechanical tuning structures have been designed and used, both of the pivoted lever type and of the sliding bar or plunger type. However, in both types of tuners a positioning member is used which has a pair of engagement surfaces on opposite sides of its longitudinal axis that are adapted to be engaged by a setting device or cam carried by the tuning arm or plunger.

Different arrangements have been used for the purpose of adjusting the position of the setting device which engages the positioning member that in turn operates a tuning element, such as the rotor of a condenser.

One great difiiculty encountered in the manufacture of radio tuning devices is to get a structure in which wobble and lost motion are elimihated, so that on pushing the slidable member or plunger into tuning position, it will always move the positioning member that operates the tuning element to the same position; and on release of the push button, so it may return to normal position, it does not shift thetuning position of the positioning member. Where there is any side or up-and-down play or wobble in the slidable member, as is apt to be the case with present constructions, the tuning will vary enough to throw the set off" the peak of the resonance curve.

It is therefore the principal object of my invention to provide a tuning structure which eliminates the difficulties heretofore mentioned by providing a construction in which all side and upand-down play or wobble is eliminated, whereby the highest efiiciency is obtained from the tunable circuit supplying the output of the radio receiving set.

Another object of my invention is to provide a construction in which the parts may be quickly adjusted during assembly operation to eliminate the side play and wobble so common in other types of construction.

Another object of my invention is to provide a construction which will attain the prior objects mentioned in a relatively cheap and inexpensive manner, and in which the parts may be quickly and accurately assembled.

Thes and other objects will appear to one skilled in this particular art from a reading of the following specification taken in connection with the annexed drawings, wherein:

Figure 1 is a part-transverse sectional and elevational view through one form of a tuning structure about twice the size of a'working unit.

Figure 2 is a sectional view along the line 2-2 of Figure 1.

Figure 3 is a view on the line 3-3 of Figure l in front of one of the tuning units comprising the structure. a

Figure 4 is a view of the rear end of the sliding unit per se at the position 4-4 of Figure 1.

Figure 5 is a view on the line 5-5 of Figure 1 looking down on the top of the body portion of the slidable member.

Figure 6 is a View of the bottom of the slidable plate or the underside of Figure 5. 7

Figure 7 is a view on the line 'l-l of Figure 1 or a top plan view of the retaining member per se.

Figure 8 is a fragmentary view of a portion of the bottom of the frame about-on the line 8-8 of Figure 1 and over which oneend of the slidable member of Figure 5 is positioned.

Figure 9 is a view of a modified form of slidable tuner with the push button, setting device, positioning member and other parts eliminated to better illustrate just the slidable member and its supporting means. r I I Figure 10 is a view on-the line-lll-IO of Fig ure 9.

Figure 11 is a view onthe line ll-H of Fig ure 10.

Figure 12 is a plan view showing a further modified form of construction.

Figure 13 is a part-sectional and part-elevational view on the line l3-'-|3'of Figure 12. 7'

Figure 14 is a view on the line l4-l4 of Figure 13. l

Figure 15 is a view similar to Figure showing a modified form of construction.

In the various views, wherein like numbers refer to corresponding parts,.l is the bottom portion of a frame, one end plate 2 of which is illustrated, the frame preferably being of one piece of suitable material, preferably metal such as steel treated to prevent corrosion. The frame carries a positioning member or bar 3 having arms at its onposite ends, one of which, 4, is illustrated as being pivoted at 5 to the end plate 2. Tosecurely hold the end plates 2 so that they cannot be readily sprung, a tie rod 31 passes between the end plates and is locked to each end plate by nuts 38 on the tie rod, thereby clamping each end plate securely between the pair of nuts. vided with holes 6 for attachment to a suitable 14, but

.The arms 4 are prolink or other mechanism for connection to a tun ing element which is not shown, as the present invention is only directed to the structures illustrated.

The base of the frame I has recesses or raceways I and 8 formed therein on opposite sides of the pivotal axis 5. Preferably the recess 1 of each pair of recesses is somewhat deeper than the recess 8 for a purpose which will be presently explained. Positioned over the four recesses I and 3 in'the frame I, is a slidable plate or member 9 having a pair of recesses or raceways I and I I at opposite ends on its top surface, and a pair of recesses or raceways I2 and I3 at opposite ends on its bottom surface. The slide 9 a lse has a slot I4 therein to receive an adjusting screw I5 which passes through a hole I6' in a strip or retaining member I! and into the frame I, where it is locked into position by any suitable means such as a lock nut I8. The retaining member II has recesses I9 and 29 on its bottom surface which are in cooperative relationship with the recesses or raceways Ill and II of the slidable member 9 when the retaining member is POSi? tioned thereover as shown in Figures 1 and 2 Positioned in these various raceways are balls or anti-friction members 2I. However, it is to be noted that, as shown in Figure 2, the ball that is positioned in the relatively deep raceway I in the frame contacts with the smooth or unree cessed. surface of the slide plate 9.

The retaining member IT has a lug 22 having a hole 23 therein to which one end of a spring. 24 is attached. This spring is shown in dotted lines in Figure l as the sectional view of Figure 1 istaken on the opposite side of the spring which does not show in this section. The other end of the spring 24- is attached to a lug 25 through the medium of a hole 26 in this lug.

The. slidable member 9 has a vertically projecting portion 21 which carries a pivot pin 28 that in turn s pports a setting deviee 29. The setting device 29 has a lug 3,0 thrown outwardly therefrom to receive one end of a spring 3 I that asten t a 1 2 o he o t n part 21. The part 21; has lugs 93 and 34 formed there- 'fromto' receive an adjusting screw 35-, the inner end of which contacts with the lower portion of the; setting device 29. It will be understood that the spring 3| is strong enough to continuously and securely hold the setting member inengagement with the end of the adjusting screw 35.. It is to be understood that the: reduced end 35 is adapted to receive a push button which fits over it and also conceals the adjusting screw 35..

It will be noted that the slidable member 9 is formed and punched from one piece of: suitable metal; likewise, the retaining member II which has sufficient resilience so that when the adjusting screw I5 is set up, the retaining member will spring sufficiently so as to properly position. the balls in their respective raceways. and yet allow very easy movement. of the slidable member in its tuning operation, it being further understood that the spring 24 is used to return the slidable member 9 to normal position after having been moved to a tuning position, whereby the setting member 29 engages the positioning member 3 on opposite sides of the pivotal point 28- and on opposite sides of the pivotal point 5 of the positioning member. In tuning in any given station, the tuning device, such as a condenser, is turned manually by suitable control means to the proper tuning position and. held there while the slidable member 9 is moved so that the setting member 29 engages the positioning member 3 which has been turned by the setting of the condenser. Then the adjusting screw is moved until it engages the setting member 29 in opposition to the spring 3i. Thus, each slidable unit may be tuned to any given station.

In Figure 9 the slidable member 39 is an extremely simple construction comprising a relatively thin plate or bar having spaced raceways 40 and M preferably formed directly in the edge of the bar by striking the bar with a suitable tool to split and spread the metal. A single raceway 42 is similarly formed in the upper edge of the strip 39.

The frame I is provided with oppositely positioned raceways 43 and 44 to cooperate with the raceways in the strip 39. Anti-friction members or balls 2I are positioned in these raceways when the strip 39 is assembled in the frame. Extending across the end plates 2 of the frame is another frame member 45 which is fastened to the end plates 2 in any satisfactory manner as by upsetting the metal of the end plate over the ends of the cross-bar 45. As shown, the cross-bar 45 forms a channel and has portions 46, one to. each slidable member 39, partially separated as by longitudinal slits 4.1 and transverse slits 48 from the base portion of the channel,

Immediately adjacent. the cross-slit 48,. the portion 45 is formed at 49 into a raceway to cooperate with the raceway 42 in the slide 39. Also, the portion 45 is provided with a hole. to receive an adjusting screw 59. whereby the portion 46.- which becomes more or less resilient due to the slits previously mentioned -may be sprung or adjusted by the set screw 58 to put the necessary tension on the bearings, yet at the same time allow them to move easily for the tuning operation.

Since the application of the setting. device and positioning member and. push button may take any one of several desired forms, they are not shown in connection with Figures 9, l0 and 11 as well as in the form shown. in Figures 12, 13 and. 14. In this. lastementioned form, the construction is quite similar to that shown in Figures 9 to 11,. except the top'cross-framemember 5| does not have the slitted portions 45 therein, but does have the same raceways 49 and set screws 59 to apply pressure to the slide 39 which is slotted at, 52 so that the two portions on. opposite sides of the slot will have some resilience and canv be i ht y sprun o, 9.612 h p p r adi'ust ment of the raceways. I have found that it is not absolutely necessary to. use the set screws 50 in all" cases, as the cross-frame member 5| may have its ends fastened, as by staking; to the. end members of the condenser-fr'a-me-and apply sufl?l cient pressure tothe parts of the slide 39,0pposite the slot 52, to take up all irregularitiesi'n manufacture andgive a smooth-acting bearing. While I have shown a. single slot 52 in the slide 39; a plurality of slits or slots may be provided in the slide to increase its resilience at the position of the bearings.

' In Figure. 15 the slide 39 has its opposite edges or portions thereof turned, over at 53 and 54,. with ats ar d o me pectively therein... The seat 55 cooperates with the seat 49 in; the; 0. 2 .58- frame member 5 I, and the seat-43 cooperates; with the seat 56 in the. bottom frame member I- in conjunction with the balls 2 I. The construction of Figure 15 may be used alone or in combination with the form shown in Figure 13.

By reason of the constructions herein described, the slidable members carrying the setting device can be quickly and cheaply made with suitable tools, and assembled very rapidly and accurately, and when the assemblies have been made, as described, there is absolutely no upand-down motion at either end of the slide, or any side-play or wobble of any kind, and an accuracy of setting and tuning is secured that, so far as I am aware, is not present in any priorart structure.

In all the forms heretofore referred to, each is provided with means for holding the slide or slidable member in operative position in the frame, yet the precise details comprising the means diifer from each other. Consequently, I do not Wish to be unduly limited in the interpretation of the accompanying claims.

What I claim is:

1. In a structure for operating a positioning member which actuates a tuning member of a radio set, a frame member having recesses on opposite portions of the frame, a slide plate positioned over said recesses and having certain recesses therein cooperatively positioned over certain of the recesses in the frame, anti-friction members in said cooperative recesses and retaining means fastened to the frame for holding the slide plate in operative position on the frame, said retaining means having oppositely positioned recesses with anti-friction members located therein in engagement with said slide plate, and a setting device adjustably carried by the slide plate for engaging said positioning member.

2. In a structure for operating a positioning member which actuates a tuning member of a radio set, a frame member having recesses on opposite portions of the frame, a slide plate positioned over said recesses and having certain recesses therein cooperatively positioned over certain of the recesses in the frame, anti-friction members in said cooperative recesses and retaining means fastened to the frame for holding the slide plate in operative position on the frame, said retaining means having oppositely positioned recesses spaced across the width of the slide plate intermediate the recesses in the frame with antifriction members located therein in engagement with said slide plate, a setting device adjustably carried by the slide plate for engaging said positioning member and resilient means coacting between the slide plate and the retaining means for returning the slide plate to normal position after having been moved to tuning position.

3. In a structure for operating a positioning member which actuates a tuning member of a radio set, a frame member having a pair of recesses on opposite portions of the frame member, a slide plate positioned over said recesses and having a recess at each end located on that side of the slide next to the frame member and over a recess in the frame member, the slide also having at each end a recess on its top side away from the frame member, a retaining member fastened to the frame over the slide and having a recess at each end in cooperative relation with the recesses in the top side of the slide, balls in all of said recesses, means for returning the slide plate to normal position after having been operated, and a setting device adjustably carried by the slide plate for engaging said positioning member.

4, In a structure as set forth in claim 3, further defined in that one set of recesses in trans verse alignment across the frame member is deeper than the other two recesses of the set associated with a given slide plate, and the balls therein engage flat portions of the slide plate.

5. In a structure as set forth in claim 3, further defined in that the retaining member is approximately the same length as the slide plate and is held to the frame member at approximately the central part of the retaining member.

6. In a structure as set forth in claim 3, further defined in that the returning means comprises a lug on the retaining member and a lug on the rear end of the slide plate, and a tension spring anchored to and between said lugs.

7. In a tuning structure for a radio set including a frame and a postioning member for actuating a tuning element and a push-button slidable member carrying an adjustable setting device for engaging said positioning member; cooperative ball races in both the frame and slid,- able member with balls therein and means for holding the slidable member in operative position on the frame.

8. In a tuning structure for a radio set including a frame and a positioning member for actuating a tuning element, a push-button slidable member carrying an adjustable setting device for engaging said positioning member, cooperative ball races in both the frame and slidable member with balls therein, a retaining member fastened to the frame for holding the slidable member in operative position, the slidable member and the retaining member having cooperative ball races with balls therein.

9. In a tuning structure for a radio set including a frame and a positioning member for actuating a tuning element, a push-button slidable member carrying an adjustable setting device for engaging said positioning member, cooperative ball races in both the frame and slidable member with balls therein, a retaining member overlying the slidable member and both having cooperative anti-friction bearing parts, and means for adjustably fastening the retaining member to the frame so as'to properly seat all the bearmgs.

10. In a tuning structure for a radio set including a frame and a positioning member for actuating a tuning element, a push-button slid able member carrying an adjustable setting .device .for engaging said positioning member,cooperative ball races in both the frame and slidable member with balls therein, means for resiliently holding the slidable member in operative position on the frame, said means comprising a retaining member capable of being sprung and overlying a part of the slidable member, both the slidable and retaining member having anti-friction bearings positioned therebetween, and an adjusting screw going through the retaining member into the frame for springing the retaining member.

11. In a tuning structurefor a radio set including a frame and a positioning member for actuating a tuning element, a push-button slidable member adapted to carry an adjustable setting device for engaging said positioning member, said slidable member being a relatively thin strip with ball races positioned on opposite edges,

the strip being positioned on its bottom edge in cooperative relation with ball races formed in the frame with balls therein, and a retaining member fastened to the frame and having a ball race therein to cooperate with a race with a ball therein in the upper edge of the strip-slidable mem-- ber. i

In a tuning structure for a radio set including a frame and a positioning member for actuating a tuning element, a push-button slidable member adapted to carry an adjustable setting device for engaging said positioningmemher, said slidable member being a relatively thin strip with ball races formed directly in the opposite edges of the strip, the frame having ball races formed therein and means for positioning and retaining the strip in edgewise position over the races in the frame, the retaining means having a ball race therein to cooperate with a raceway in the upper edge of the strip, the races having balls therein and means for adjusting the retaining means to properly seat the strip-slidable member in its bearings,

13'. A tuning structure as set forth in claim 12,

further defined in that the retaining means comprises a metallic member extending longitudinally of the frame and having a section carrying the raceway resiliently formed therein, and an adjusting screw for adjusting the tension of this section on the strip-slidable member.

14. A tuning structure as set forth in claim 12, further defined in that the retaining means comprises a member extending longitudinally of the frame and carrying means for resiliently supporting the ball race which cooperates with the ball; and raceway in the upper edge of the stripslidab'le member.

15. In a tuning structure for a radio set including a frame and a positioning member for actuating a tuning element, a push-button slidable member adapted to carry an adjustable setting device for engaging said positioning meme her, said slidable member being a relatively thin strip with ball races formed directly in the opposite edges of the strip, the frame having ball races formed therein and means for positioning and retaining the stripin edgewise position over the races in the frame, the retaining means having a ball race therein to cooperate with araceway in the upper edge of the strip, the races having balls therein, the striphavin'g a lo'ngitudinal slot therein to provide some edgewise resilience in the strip, while the retaining means has screws fastening it to the frame whereby the screws can, through the retaining member, apply a spring action to the slotted strip-slidable mem-' ber.

16.- In a radio tuning apparatus including frame members and a slidable member supported by the frame members and adapted to carry a setting device for engagement with a positioning member for actuating a tuning device; means for taking out all wobble of any kind and lost motion during the tuning operation of the slidable meniber, said means including anti-friction bearings positioned on opposite parts of the slidable merriber between it and the frame members.

17. In a radio tuning apparatus including frame members, a slidable member supported by the frame members and adapted to carry a setting device for engagement with a positioning member for actuating a tuning device, means for taking out all wobble of any kind and lost motion during the tuning operation of the slidable member, said means including anti-friction bearings positioned on opposite parts of the slidable mem-- ber between it and the frame members, and means carried by one of the frame members for adjusting the slidable member on its anti-friction bearings.

18. In a tuning structure for a radio set including frame members and a positioning member for actuating a tuning element carried by at least some of the frame members and a pushbutton-slidabl'e member adapted to carry an adjustable setting device for engaging said positioning member; and cooperative ball races formed directly in both the frame and slidable members with balls in said seats for positioning said slidable member in the frame members.

19. A tuning structure as set forth in claim 18, further defined in that the slidable member is a relatively thin, fiat strip of suitable material, and the ball seats are formed in an edge portion thereof.

20. A tuning structure as set forth in claim 18, further defined in that the slidable member is a relatively thin, fiat strip of suitable material, and the ball seats are formed in bent-over edge portions thereof.

21. A tuning structure as set forth in claim 18', further defined in that the slidable member is a relatively thin, fiat strip of suitable material, and

' the ball seats are formed in' an edge portion thereof, and means comprising at least one longitudinal slit or slot in said strip for securing some resilience between the frame and slidable mein here to smoothly accommodate said bearings; STANLEY'S. CRAMER. 

